Term test Ch. 19

Question 1

Hierarchical control

Answer 1

Genes expressed at each stage control expression of genes at later stages

Question 2

What is an oocyte

Answer 2

Unfertilized egg cell

Question 3

Bicoid

Answer 3

Maternal effect gene which controls the development of anterior end

Question 4

Nanos

Answer 4

Maternal effect gene which controls the development of posterior end

Question 5

Maternal-effect genes

Answer 5

Genes that are expressed by mother which affect the phenotype of the offspring

Question 6

What is a polarized cell

Answer 6

When gradients of macromolecules such as mRNA for bicoid and nanos are in high concentrations at one side of the cell but not the other.

Question 7

Where does the mRNA of bicoid and nanos come from?

Answer 7

Both are synthesized by mother and imported into the oocyte during oogenesis

Question 8

What are Caudal and Hunchback

Answer 8

They are transcription factors:
Bicoid protein represses translation of Caudal
Nanos protein represses translation of Hunchback

Question 9

What do Hunchback and Caudal control

Answer 9

Hunchback targets anterior and Caudal targets posterior

Question 10

What are gap-genes

Answer 10

Genes controlled by maternal effect genes and encode for transcription factors

Question 11

What are pair-rule genes

Answer 11

Genes that encode for transcription factors and are mainly used in segmented embryos of insects

Question 12

What are homeotic genes

Answer 12

Genes that encode for transcription factors in animal development and are expressed even after early development genes shutdown

Question 13

Homeodomain

Answer 13

60 amino acid sequence that promotes or repress transcription

Question 14

Hox genes

Answer 14

Genes in embryonic development of structures such as the nervous system

Question 15

Evolutionarily conserved genes

Answer 15

Genes similar in sequence even among distantly related organisms, usually carry vital function such as eyes

Question 16

What gene is important in the development of eyes

Answer 16

The Pax6 gene, it is the master switch but not the entire blueprint

Question 17

Gain-of-function mutation

Answer 17

Gene expressed at the wrong place or time

Question 18

Loss-of-function mutation

Answer 18

Gene not expressed properly

Question 19

How do transcription factors work

Answer 19

They bind to short DNA sequences adjacent to gene (also called cis-regulatory elements) and act as repressors or activators.

Question 20

Teratogen

Answer 20

Agents that cause abnormalities following fetal exposure such as retinoic acid

Question 21

Antennapedia gene

Answer 21

Gene responsible for leg growth

Question 22

Ubx gene

Answer 22

Gene responsible for thorax growth

Question 23

dll gene

Answer 23

Gene responsible for appendage development